Consumer products, such as fabric care products, personal care products and home care products are well known in the art and usually comprise one or more perfumes to impart the consumer product and/or a substrate treated or applied with the consumer product with a fragrance; however, these perfumes dissipate over time from the consumer product or substrate. Another problem with perfumes in consumer products is that they are released prior to an optimal delivery time, and the user of the consumer product is deprived of experiencing the perfume's fragrance. For example, it is desirable for a perfume to be present on clothes treated with a detergent and/or fabric softener long after such treatment, and there is a tendency for perfumes to evaporate or diffuse from the clothes over time.
Thus attempts have been made to minimize the loss of perfumes due to volatility and evaporation, and to optimize the release of the perfume's fragrance. One such approach has been to encapsulate the perfume within a shell to create a fragrance microcapsule.
The calculated log P (C log P) of many perfumes is known in the art, and has been reported, for example in the Ponoma92 database, available from Daylight Chemical Information Systems, Inc. (Daylight CIS) Irvine. Calif. Methods of calculating C log P are also known in the art. Perfumes with lower C log P values may be more volatile and exhibit higher aqueous solubility than perfumes having higher C log P values and are therefore preferred to be used in consumer products. However when lower C log P materials are encapsulated they may have a greater tendency to leach out of, or diffuse out of the shell into the consumer product (preventing optimal delivery of fragrances), and the perfumes may eventually diffuse out of the consumer product prior to use by the consumer.
Methods to prevent the leaching of perfumes from fragrance microcapsules have been developed. These may include coating the interior or exterior of the shell with one or more polymers or incorporation of stabilizing agents in the core. However, there is a continuing need to develop systems that deliver fragrances. More efficient delivery systems, or more stable encapsulated perfumes may result in more efficient use of perfumes, thus decreasing manufacturing costs.
When fragrance microcapsules are incorporated in consumer products containing solvents and/or surfactants, e.g., shampoos, stability problems may arise. The encapsulated perfume may leach out of the shell. The shell may also absorb a solvent, surfactant, or any other material in the consumer product, causing the shell's integrity to be compromised. The shell may swell because additional materials diffuse into the shell or the core, or the shell may shrink as materials of the core diffuse out of the shell. Indeed, components of the shell may even diffuse into the consumer product.
Similar considerations apply to the delivery using microcapsules of other materials providing benefits to the consumer, such as flavorants or antibacterial materials.
Thus there is a need to develop compositions suitable for use in compositions that provide for stability of microcapsules encapsulating fragrance or antimicrobial materials. WO 2008/005693.
In certain applications, also the deposition of encapsulated benefit agents is improved by coating the encapsulated benefit agent with a polymer. In general, such polymer coating improves the deposition of the encapsulates. Also surprisingly, while decreasing leaching of the PRM's out of the encapsulate when in the finished product, the polymer coating allows improved release of the PRM's in the headspace when the encapsulate is deposited on the surface to be treated.